The present invention generally relates to a copying machine having a transparent document support of a corner aligning type and, more particularly, to a device incorporated in the copying machine for the detection of the size or the presence or absence of a document on the document support.
The term "corner aligning type" referred to hereinabove and hereinafter is to be understood as meaning the document support which is generally rectangular in shape having four right-angled corners, one of the corners being utilized as an alignment corner with which a corresponding one of the corners of a document to be copied is, when the document is placed on the document support, aligned in readiness for the actual copying operation. This is in contrast to the type of document support, hereinafter referred to as "center aligning type", which is generally rectangular in shape having a pair of opposite ends and a pair of opposite sides, either one of the ends or one of the sides having an index marking with which a center line of a document to be copied has to be aligned when the document is placed on the document support.